PDCA CYCLE

7 Basic ToolsÄ Flow ChartÄ Check SheetÄ HistogramÄ Pareto ChartÄ Scatter DiagramÄ Cause & Effect DiagramÄ Run Chart/Statistical Process Control

Flow Charts are used to...

• document a process• improve understanding• reveal differences in methods• uncover non-value added activities

Flow Chart Example: Self-Serve Gas Before Improvement

Drive in check price self serve? to pumpshut offengine

walk to paystation

yes

no

check card transmit approved?turn onpump

yesno

backto car

pumpgas

walk tobooth

wait

employeetotalscharges

checkaccuracy

preparereceipt

signcopy

copy tofile

copy towallet

return to car

on the roadagain

Flow Chart Example: Self-Serve Gas After Improvement

Drive incheckprice self-serve?

no

yes

go topump

shut offengine insert

cardin pump

checkcredit card

wait

approved?

no

yes

wait forreceipt

store in system

copy towallet

on the roadagainpump gas

CHECK SHEETS

Data collection & analysis

• Contents mixed• Poor taste• Low temperature• Utensils dirty• Price issue• Other

Histograms

Graphical descriptive statistics (mean and standard deviation)

Bell-Shaped

Uniform

Bimodal

Pareto Charts

• Similar to a histogram, used to find “most popular” category

• Based upon the Pareto principle...

Basic Pareto Diagram

Slow d

own

Mor

e ex

ampl

es

Leve

l too

high

Too m

uch

work

Remem

ber p

rere

quisi

tes

Seque

nce

Wro

ng0

1

2

3

4

5

6

Complaints courtesy of my Spring OPC class

Alternate Pareto Diagram

Slow d

own

Mor

e ex

ample

s

Leve

l too

high

Too m

uch

work

Remem

ber p

rere

quisi

tes

Seque

nce

Wro

ng0

1

2

3

4

5

6

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

Count

Cumulative %

Complaints courtesy of my Spring OPC class

Scatter DiagramE

xam

Sco

re

Homework Problems

Class 1

Class 2

Graphical descriptive statistics (correlation)

Cause & Effect Diagrams

• Also known as fishbone diagrams or Ishikawa diagrams, after their creator Kaoru Ishikawa

• In general, used to find and cure causes (NOT symptoms) of problems

Cause & Effect Example

LATE PIZZADELIVERYFRIDAY & SATURDAY

MANPOWERMETHODS

MATERIALSMACHINES

Drivers lost

Chef late

Lack ofingredients

Smallovens

Largeordersnafus

Badcars

Poordispatching

Run Chart

• Graphical descriptive statistics (trend)

Defectives/Sample

0

1

2

3

4

5

6

7

8

9

10

1 2 3 4 5 6 7 8 9 10

Statistical Process Control

• Finds “special” variation• General form of limits• Center line = Average

3 *Average Variation

Control Chart

0

0.02

0.04

0.06

0.08

0.1

0.12

1 2 3 4 5 6 7 8 9 10

p

pbar

UCLp

LCLp

* Not the variance